Neopentyl glycol hydroxypivalate (NHP) is used, inter alia, as a component of inside coatings of cans, in order to increase the impact strength of the inside coatings. Processing of NHP for subsequent use is usually carried out by an NTIP melt being ;applied to a cooling belt via a droplet former. Flat, flaky granules are formed in the process which tend to cake together when stored in packages and containers.
Said caking then impedes proportioning and removal of the granules from the packages and containers.
DE-A-35 22 359 discloses a process for the processing of crystalline, organic materials such as neopentyl glycol hydroxypivalate so as to result in a product which is more readily free-flowing. This involves a pulverulent material being compacted in a twin-shaft screw machine having corotating shafts or a molten material being crystallized and compacted, at bulk temperatures which are from about 1 to 20.degree. C. below the melting point of the material used. The material is then expelled, through a heated perforated plate, into a zone having a lower pressure.
The perforated plate is heated to a temperature of from 1 to 30.degree. C. above the melting point of the material, so that the individual crystals being passed past the wall of the perforated plate fuse to produce a film which, after it has solidified, forms a firm corset for the compacted crystalline material. In a downstream zone the extrudates are reduced in size and cooled. The flowability of the granules thus obtained is not adequate for all applications.
DE-C-32 09 747 discloses an apparatus for preparing granules from a melt, in which a two-phase mixture from a melt which contains crystal seeds is applied to a cooling belt by means of a rotor droplet former, hemispherical granules being obtained in the process.